Effect of penicillin on the cell wall of Bacillus subtilis

Abstract

Exposure of growing Bacillus subtilis cultures to penicillin has no observable effect on the nitrogen and phosphorus content of the whole cells and only a small effect on the nitrogen and phosphorus content of the cell-wall fraction. Muramic acid, glucosamine, alanine, glutamic acid, diaminopimelic acid and ammonia are the major nitrogenous components of B. subtilis cell walls, accounting for nearly all of the cell-wall nitrogen and amounting to 52% of the cell-wall mass. Incorporation of carbon from 14C-labelled sugar in the medium into cell constituents was studied. Incorporation into whole cells was inhibited 20% and incorporation into cell walls was inhibited 88%. Incorporation into cell protein was not inhibited. The specific activity of various cell-wall components showed that penicillin inhibited incorporation of muramic and diaminopimelic acids into cell wall more completely than incorporation of other cell-wall components.